Naked Mole Rats’ Acidic Survival Gives Clues on Developing Tolerance to Hostile Environment

A new study that is being done on the rodents describes how these rodents adapt to the acidic environment that even humans will not able to tolerate. 

"In the tightly crowded burrows of the African naked mole-rats' world, carbon dioxide builds up to levels that would be toxic for other mammals, and the air becomes highly acidic. These animals freely tolerate these unpleasant conditions," said Thomas Park, professor of biological sciences at University of Illinois at Chicago and principal investigator of the study. This research may offer clues to relieving pain in other animals and humans.

"Much of the lingering pain of an injury, for example, is caused by acidification of the injured tissue," Park said.

"Acidification is an unavoidable side-effect of injury," he said. "Studying an animal that feels no pain from an acidified environment should lead to new ways of alleviating pain in humans.

 Specialized nerve fibres are been activated by acidic fumes in the nose of a mammal. And this stimulates the trigeminal nucleus, a collection of nerves in the brainstem, which in turn elicits physiological and behavioral responses that protect the animal.

The naked mole rats were placed in a system of cages in which some areas contained air with acidic fumes. These animals were allowed to roam freely, and the researchers noted the time the animal spent in each segment. The researchers then compared the behavior of those rates with those of the laboratory rats, mice, and a closely related mole-rat species that likes to live in comfy conditions.

"The naked mole-rats spent as much time exposing themselves to acidic fumes as they spent in fume-free areas," Park said. "Each control species avoided the fumes."

Based on the study, the researchers were able to quantify the physiologic response to exposure to acidic fumes by measuring a protein, c-Fos, an indirect marker of nerve activity that is triggered when nerve cells fire. In naked mole-rats, no such activity was found in the trigeminal nucleus when stimulated. In rats and mice, however, the trigeminal nucleus was highly activated.

The naked mole-rats' tolerance of acidic fumes is consistent with their adaptation to living underground in chronically acidic conditions, Park said.

This study was published in PLOS ONE.